Electric fuel pump control for internal-combustion engines



P 9, 1952 c. PARKER 2,609,809

ELECTRIC FUEL PUMP CONTROL FOR INTERNAL-COMBUSTION ENGINES Filed Sept 18, 1950 IN VEN TOR.

Patented Sept. 9, 1952 ELECTRIC FUEL PUMP CONTROL FOR INTERNAL-COMBUSTION ENGINES Leland G. Parker, Elmira, N. Y., assignor to Bendix Aviation Corporation, a corporation of Delaware Application September 18, 1950, Serial No. 185,446

2 Claims. (01. 123-179) The present invention relates to an electric fuel pump control for internal combustion engines and more particularly to means for automatically rendering an electric fuel pump operative when the engine starter is actuated, and for thereafter maintaining the operative condition of the pump as long as the engine is running, but breaking the pump circuit when the engine stops.

Electrical fuel pumps for internal combustion engines have the advantage over the more conventional mechanically-operated pumps in that the former go into full activity immediately upon closure of the control switch, so as to promptly fill a depleted carburetor bowl, whereas, under like conditions when an engine driven pump is used, a considerable period of abortive cranking maybe required to fill the fuel line and carburetor bowl preparatory to operation of the engine. On p the other hand, electrical pumps have the disadvantage that if the pump circuit is inadvertently left closed while the engine is stopped and unattended, or in case of a collision or upset, the continued operation of the pump might constitute a fire hazard. It is an object of the present invention to provide a novel electric fuel control for closing the pump circuit substantially concomitantly with actuation of the starter, and for holding it closed as long as the engine is self operative.

It is another object to provide such a device in which the pump circuit is controlled by contacts which are initially closed by means actuated from the starter circuit, andjthereafterheld closed by means responsive to pressure in the lubricating system of the engine.

Further objects ,and advantages will be apparent from the following description taken in of one preferredformof the invention;

Fig. 2 is a similar view of a second embodiment. Fig. 3 is a similar view of athird embodiment of the invention; and

Fig. 4 is a similar view of a modification of the embodiment shown in Fig.3.

In Fig. 1 of the drawing thereis shown an electrical system for an internal combustion engine not illustrated comprising a battery I grounded at 2 and connectedthrough a lead 3 and ignition switch 6 teen automatically operated pump control switch indicated generally by numeral 5. l

A lead 6 connects the switch to'thefuel pump P, which is grounded at ltocomplete theactuat- 1 ing circuitforthe pump. 3 p l i in the wall of the chamber, insulated therefrom;

and blade Isis connected by lead [5 to the ignition switch 4 while the blade I4 is connected to the pump lead 5. The free end of the blade [3 carries a contact [5, and the free end of blade i l carries a contact ll, which contacts are normally spaced from each other as illustrated.

As here illustrated, the starting system comprises a lead [8 attached to the battery lead 3 and adapted to be connected to the starting motor SM by a magnetic starting switch 19. The starting motor is grounded at 2| to complete the starting circuit. Closure of the starting switch I9 is effected by'means of a coil 22, one end of which is connected to the lead l8, and the other end of which is arranged to be grounded at 23 through a manually operable switch 24. A portion of the current supplied to the starting motor when the starting switch i9 is closed, is conducted by the lead 25 to an insulated terminal 26 mounted on the wall of the chamber 8 of pump switch 5, and a strip of thermostatic bimetal 2! is connected at one end to the terminal, and at its other end is attached to a block of insulating material 28 suitably fixed on the contact carrying blade 13. A flexible lead 29 connects the lower end of the bimetal strip to the casing of the switch 5, which casing is grounded as indicated at 3| in orderto complete the electrical circuit through the'thermostat 2?. The thermostat is so arranged that when it is heated by current passing therethrough, it will expand and flex the blade [3 so as to move the contact I'B into engagement with the contact ll on blade I4.

Means responsive to the pressure in the lubrieating system for holding closed the contacts it, ll is'provicled in the form of a projection 32 "mounted on the upper side of the flexible di- 1 aphragm l i in position so thatupward: movement In the operation: of this embodiment of the 3 invention, starting with the parts in the posif the starting switch tions as illustrated, the ignition switch 4 is first closed in order to render the ignition system of the engine operative, and the manual starter control switch 24 is then closed. Consequent closure of the magnetic starting switch l9 initiates the cranking operation, and at the same time causes current to flow through the thermostat 21 whereby it expands, moving contact [6 into engagement with contact l! and thereby completing the pump control circuit through the ignition switch 4, thus bringing the fuel pump into operation.

As soon as the engine is rotated sufficiently to generate pressure in its lubricating system, the diaphragm ll of pump control switch is flexed upwardly, thereby pressing contact I! against contact 16 and thereafter holding these contacts closed. When the engine starts, the manual switch 24 is opened, thus deenergizing the starting system and the thermostat 21, but contacts 15, H are held closed by the oil pressure so long as the engine is running. Should the engine stop forany reason, contacts 15, ll return to their normal open position so that the fuel pump is immediately deenergized and will not be reactu- .ated until the starting system is again brought into use. a

In Fig. 2 of the drawing, the parts are generally similar to those illustrated in Fig. 1, however, ..the fuel pump control switch mechanism Bahere embodies a mercury switch 35 and electromagnetic means for initially causing closure thereof. Switch .35 comprises a sealed capsule 31 containing a globule of mercury 38, .and contacts 39 and 4!. The capsule 31' is rotatably mounted on a bracket 42 fixed to the interior of the casing 35 of the switch mechanism 5a, and a switch stem 43 of magnetic material fixed to the capsule 3'! normally rests on a projection 44 of insulating material mounted on the flexible diaphragm I l An electromagnet 45 is mounted on a bracket 46in the interior of the casing 36 in position to attract the switch stem 43 and thus cause rotation of the mercury switch 35 so as to bring the globule of mercury into position to connect the contacts 39, 4| and thus close the switch. Electromagnet 45 is connected by a lead 25 to the starting switch l9 and is grounded through lead 29 so that closure of the starting switch causes a energization of the electromagnet.

In the operation of this embodiment, closure I9 causes the electromagnet 45 to rotate the mercury switch 35 so as to cause energization of the fuel pump P, and such energization is maintained as long as the engine is runningv by .virtue of the pressure of its lubricating system which flexes diaphragm II j-upwardly, thus holding the mercury switch in closed position.

7 In Fig; 3 of the drawing the electrical system of the engine is in general the same as previously illustrated, but a pump control switch 5 is provided in which the pump controlling contacts are .initially closed by an electromagnet energized The upper end the fuel pump P. Spring blade 56 also carries at an intermediate point a contact 59 which is arranged to cooperate with a contact 62 adjustably mounted in the insulating block 51, and connectedby a lead 63 to an indicator lamp L Which is grounded at 64.

Means for intially closing contacts 58, 6| upon actuation of the starting motor SM is provided in the form of a solenoid 65 within the casing 50, one end of which is connected to the terminal 55 and lead 25 from the starting switch, and the other end of which is grounded as indicated at 55. -A magnetic plunger 61 is slidably mounted in the solenoid .65 and normally rests on the flexible diaphragm ll but is insulated therefrom as shown at 68. The upper end of plunger 6! is operatively connected by a section of in sulating material 59 to the blade 56.

In this structure, closure of the ignition switch 4 connects the contact-carrying blade 56 to the battery, but no current flows since contacts 58, BI and 59, 62 are normally open. When the relay switch 24 is closed, the starting switch 19 causes actuation of the starting motor, and at the same time energizes the solenoid 65, which draws the plunger 61 upward, closing contacts 58, 61., thereby causing actuation of the fuel pump P. As soon as the rotation of the engine builds up the oil pressure to the required minimum, the diaphragm li forces plunger 61 upward, flexing the spring blade 56 and closing contacts 59, 62 so as to light the panel lamp L. Thereafter the fuel pump contacts 58, 6| and the lamp contacts 59, 62 are held closed by the oil pressure as long as the engine is operative, but are permitted to open when the engine stops, or in case of failure of oil pressure for any other reason.

The solenoid 65 may, of course, be designed to exert sufiicient force to close both sets of contacts if it be desired to have the panel lamp light as soon as cranking starts, without waiting for the oil pressure to build up.

In Fig. 4 of the drawing, a more compact form of the structure illustrated in Fig. 3 is shown in which the pump control contacts 58', 6! are mounted within, the solenoid 65' and are normally held apart by a spring 10. A magnetic plunger 67' here carries the contact 58 and accordingly is insulated from the core of the solenoid as indicated-at. In this case the indicator lamp L is wired in parallel with the pump so that t lights up when the starting system is energized, and remains lit as long as oil pressure is maintained.

Operation of this embodiment of the invention is otherwise the same as that shown in Fig. 3.

Although certain embodiments of the invention have been shown and described in detail it W111 be understood that various changes may be m de in the precise design and arrangement of the partswithout departing from th pirit f the invention.

. I, claim:

1. In a control system for electrical fuel pumps for internal combustion engines, a switch having normally open contacts, means including a solenoid and magnetic plunger for closing said switch, a. starting system for the engine including a starting switch, a control circuit for the solenoid including said starting switch, said engine having a pressure lubricating system, and means actuated by the hydraulic pressure in said lubricating system for holding the solenoid plunger in switch closing position, as long as the engine is in operation.

2. An electrical fuel pump control system as set forth in claim 1 including further a flexible blade anchored at one end and carrying one of the switch contacts on its free end, said plunger being arranged to engage the blade at anintermediate point and move the blade to close the switch when the solenoid is energized, and a signal circuit including a normally open switch having a contact located at an intermediat point 6 on said flexible blade, said hydraulic means being operative to move the plunger to bow the flexible blade and close the signal circuit switch responsive to self-operation of the engine.

LELAND C. PARKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

